Speakers under $3-4,000?

I would not buy used magnepans. The 3.6 has delamination issues that are atmosphere and age related. A new pair of Magnepans 1.7s would be a much better buy. They use foil instead of round wire for the "driver" and delamination will be minimized (or gone...).

Used Thiel CS2.4 would be a more traditional option (and my vote). They can be a touch bright but have very good bass to off set it.

Focal Electra 1027S:
Well balance, clear mids but a little light in the bass
http://www.audiogon.com/cgi-bin/cls.pl?spkrfull&1309213779&/Focal-Electra-1027S-macassar

Dynaudio C1:
Do a google search, countless good reviews.
http://www.audiogon.com/cgi-bin/cls.pl?spkrmoni&1309611046&/Dynaudio-C1-maple--pristine

Dynaudio Contour S1.4
Cheaper alternative to the C1
http://www.audiogon.com/cgi-bin/cls.pl?spkrmoni&1307511192&/Dynaudio-Contour-S1.4-cherry-m

I have not heard the Usher Mini Dancer II but they are also getting very good reviews and look very nice.

Ckoffend makes good points. I did not recommend the Thiel 2.2 because I have not heard them. There are just so many good buys out there on the used market. You can get the Revel Studio for around $4500 ($12000ish when they came out) and make your first highend buy your last (assuming it is your first)...

I do not have the Studios I am just a fan. I am using a pair of Thiel CS2.4 I bought used off a local dealer. I like the CS2.4 a lot but I often think I should have bought the Studios used off Audiogon instead because the price difference is marginal...

Now I am just too lazy (hate the hassle) to sell my CS2.4 and grab the Studio.